The following is within the scope of beating the normal game. I do not play competetively.
I've decided to pick Venusaur as my starting pokemon, and use the following moveset for tough battles:
Leech Seed
Sleep Powder
Double Team
Poison Powder/Substitute (Don't know if I NEED sub for AI opponents)
I'm sure this is a known combo. If not, the idea is that I put the opponent to sleep right off the bat with sleeping powder, hit him with leech seed, and buff my evasion with double team. When evasion is at +6 (And the 1st guy is probably dead), I hit everything else with poison+leech seed, and sit there while they wiff.
Since venusaur will have buffed evasion, I want to keep him in to tank. Since he doesn't have an active attack, I have no real way of using him at that point, thus the need to simply end my turn.
As a 4th attack, I've considered something active, such as Solar Beam, or Megadrain. Megadrain has only 5 uses in FR/LG, so eff that. Solarbeam is very cool, but I think I prefer poison powder just for the added life drain. 1/4 hp a tick sounds very nice.
I searched pretty tirelessly for a way for Venusaur to inflict a secondary status ailment, like confuse, but haven't found one. If anyone knows of a way to do this, or has any general ideas or suggestions, I'd love to hear from them.
Edit
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Quick follow up question: Do Pikachus holding "Light Balls" exit in Leaf Green? I'm not looking forward to restarting my game in emerald or something -_-
Thanks,
<- This guy